Priority is claimed with respect to Patent Application No. 99810283.4 filed in the European Patent Office on Apr. 6, 1999, the disclosure of which is incorporated herein by reference.
The invention relates to a feeder for a collator, having means for depositing sheets from a stack individually and cyclically onto a conveying device, having a gear mechanism with a powered wheel and a power take-off wheel, which are connected with the depositing means.
Feeders of this type have been produced by the assignee herein for a long time and are used for individually depositing sheets from a stack of a sheet magazine to a collecting chain. Following their removal from the stack, the folded sheets are opened by two opening drums and are dropped, straddling two catches of the collecting chain, onto the latter. So that these sheets are deposited precisely between two catches, the cycle of the feeder must be matched to the cycle of the collecting chain. An imprecise setting results in sheets being dropped off the collecting chain, which means an interruption in any case. An exact match is particularly important if a very large output is required, and if the distance between two adjoining catches of the collecting chain is not much greater than the width of the sheets. Thus, the depositing of the sheets on the collecting chain in a way wherein the cycle is as precise as possible is essential for a large output and functional dependability of a sheet collating machine.
Up to now it was necessary to turn off a device in order to match its cycle to the collecting chain, and the feeder had to be uncoupled from the gear mechanism. After adjusting the gear mechanism, it was connected again and the adjustment was checked with the machine running. As a rule it had been necessary up to now to connect and disconnect several times before the desired matching of the cycles had been achieved. This matching was particularly time-consuming in cases where a collating machine had several feeders. Moreover, the matching was not only comparatively elaborate, but also not precise since.
An object of the invention is to provide a feeder of the type mentioned in which the cycle can be matched more simply and rapidly to that of the conveying device.
The above and other objects are achieved in accordance with the invention by the provision of a feeder for a collator, comprising means for depositing sheets from a stack individually and cyclically onto a conveying device; a gear mechanism having a powered wheel and a power take-off wheel which are connected with the depositing means; and an adjusting device with which the powered wheel and the power take-off wheels are rotatable in relation to each other for adjusting a deposit cycle of the feeder.
Accordingly, the feeder of the invention has an adjusting device, by means of which the powered wheel and the power take-off wheel of the gear mechanism can be displaced in relation to each other. With such an adjustment device, an adjustment is possible while running the conveying device. An adjustment while running is not only simpler and faster, but also more accurate, since it is immediately possible to check the effect of the adjustment. Moreover, the adjustment-of the cycle is continuous, since such an adjustment device can be independent of the pitch.
Preferably the conveying device is a collecting chain, however, it can also be an opening drum, for example.
The feeder is preferably a folding feeder with a draw-off drum and two opening drums, but this is not absolutely required. The feeder can also be embodied as an insetting machine.
A particularly advantageous embodiment of the adjusting device results if, in accordance with a further development of the invention, one of the two wheels is arranged on a hollow shaft, and this hollow shaft receives a further shaft, on which the other wheel is arranged. These two shafts are displaced in respect to each other in one or the other direction for adjusting the cycle. In accordance with a further development of the invention, this takes place by means of an engagement element, which preferably can be displaced along the two hollow shafts, and which projects through slits in the two hollow shafts. One of these slits is preferably spirally shaped.
A particularly exact and simple cycle adjustment results if, in accordance with a further development of the invention, the engagement element can be continuously displaced in the longitudinal direction of the two shafts by a threaded spindle. The engagement element can be very exactly displaced by turning the threaded spindle, and thus the two shafts can be turned in respect to each other.
In accordance with a further development of the invention, a coupling is installed in the powered wheel. This results in a particularly compact structure.
The coupling is preferably designed so that it limits the torque.
If, in accordance with a further development of the invention, the torque can be controlled, it is possible to match the maximum torque optimally to the product to be deposited.
In accordance with a further development of the invention, the regulation of the torque is performed by compressed air, which allows a particularly simple and dependable regulation.
The design of the coupling allows a recoupling in the exact cycle.
An exemplary embodiment of the invention will be explained in greater detail in what follows, making reference to the drawings.